Glass press forming machine

Abstract

The individual needles of a glass feeder mechanism which control the volume of the streams of molten glass sheared into discrete gobs are displaceable to adjust the size of the sheared gobs. The controller for the motor, which raises or lowers a stream, receives positional data from the plunger, which forms the gob into a parison, and determines the Parison Formation Point for that parison and raises or lowers the needle to maintain that point at a desired plunger location.

We claim: 
     
       1. A multi-gob glass forming machine comprising a plurality of parison mold assemblies each including a plunger displaceable from a retracted position to a fully inserted position,   means for displacing each plunger from said retracted to said fully inserted position, said plungers advancing to a parison formation point where the mold cavity has become completely full and then to a fully inserted position as the formed parison cools,   means for sensing the actual position of each of said plungers throughout at least the last portion of its displacement which includes the parison formation point and for determining the parison formation point for each of said plungers, and   means for simultaneously delivering discrete gobs of molten glass to said parison mold assemblies including   a feeder bowl having an orifice plate with a corresponding plurality of openings, and   a corresponding plurality of needles individually displaceable to vary the volume of a stream of glass passing through the orifices, and   shear means for simultaneously shearing a gob from each of the streams,   computer means for determining when the displacement curve for each of said plungers becomes linear to locate the actual parison formation points for said plungers,   manually inputtable means for defining the location where the parison formation point for each of said plurality of parison mold assemblies should be located, and   means for comparing the location of the actual parison formation point as determined by the computer and the location of the desired parison formation point as inputted by the operator for each of said plungers, and individually displacing each of said needles to change the volume of the stream of glass controlled by said needle, and hence, of the gob formed therefrom to relocate the location of the actual parison formation point of the plunger to the desired location of the parison formation point as defined by the operator.   
     
     
       2. A multi-gob glass forming machine according to claim 1, wherein each of said sensing means comprises a linear potentiometer. 
     
     
       3. A multi-gob glass forming machine according to claim 1, wherein said defining means comprises manually settable input means.